1. Field of the Invention
The present invention relates to a composite processing machine having composite functions such as boring, which is also a machine tool comprising an automatic swiveling turret such as a large vertical lathe, for example.
2. Description of the Related Art
An automatic swiveling turret device, wherein a plurality of tools (tool holders) that are switched and used by swiveling are provided to a turret, and the turret is automatically swiveled relative to a turret head when the tool is switched or when the tool angle is changed, commonly has a configuration such as the following (referring to the drawings of the present example, the description appends the same symbols to the same components of the present example).
The configuration is designed so that a turret 3 provided with a plurality of tools (a plurality of cutting tools 26 replaceably provided to a plurality of respective holders 25) is swivelably fitted onto a swivel shaft part 2 secured in a protruding manner to a turret head 1, the turret also being capable of sliding back and forth along the swivel shaft part 2; a clutch device 4 is provided for disengageably locking and securing a turret indexed position by the axial sliding of the turret 3, the sliding of the turret 3 from a proximal end to a distal end causes the locked securing of the clutch device 4 to be released (unclamped), enabling the turret 3 to swivel, and the turret 3 is slid back to the indexed position after swiveling to be locked and secured (clamped) by the clutch device 4 so as to be incapable of swiveling.
Specifically, the configuration is designed so that there is provided a transmission gear 11 (an internal gear 11 that swivels about the swivel shaft part 2 as an axis) which meshes with a small transmission gear 28 driven by a swivel drive source (a servo motor) for indexing the turret 3, clutch locking parts 29 are provided to the turret head 1 as the clutch device 4, clutch engagement parts 30 for engaging with the clutch locking parts 29 in a rotation-stopping manner by concave and convex parts are provided to the proximal end of the turret 3, the engagement between the clutch locking parts 29 and the clutch engagement parts 30 is released to enable the turret 3 to swivel when the turret 3 slides from the proximal end to the distal end, the turret 3 is swiveled by an indexing swivel drive source via components such as the small transmission gear 28 and the transmission gear 11, and the turret 3 is indexed.
Also provided is a turret slide mechanism 15 for releasing the clutch engagement (for switching between clamping and unclamping), which is composed of a clutch-releasing pressure chamber 31 for channeling air from a slide-driving air supply device via a solenoid valve and thereby causing the turret 3 to slide axially to unlock the clutch device 4, and a sliding movement gap 32 enclosed by the clutch-releasing sliding of the turret 3, the sliding movement gap also being a clutch pressure chamber 32 to which air is conversely channeled by the switching of the solenoid valve, whereby the turret 3 is slid back and locked and secured by the clutch device 4.
There follows a description in further detail. An overhanging part 16 is provided to the swivel shaft part 2, the turret 3 is configured so that in both the proximal end side and the distal end side of the overhanging part 16, gaps are formed which are widened and narrowed by the sliding of the turret 3 and which are sealed by a mutual O ring or the like to achieve complete separation, one gap formed by the turret 3 and the distal end surface of the overhanging part 16 constitutes the clutch-releasing pressure chamber 31, another gap formed by the turret 3 and the proximal end side of the overhanging part 16 constitutes the clutch pressure chamber 32 which is the sliding movement gap 32, air is channeled to the clutch-releasing pressure chamber 31 by the air supply device via an air supply channel 33 provided to the swivel shaft part 2 or the overhanging part 16, thereby pushing the clutch-releasing pressure chamber 31 open and causing the turret 3 to slide to the distal end relative to the overhanging part 16 on the secured side to unlock the clutch device 4, and air is conversely channeled to the clutch pressure chamber 32, thereby pushing the clutch pressure chamber 32 open and causing the turret 3 to slide back to the proximal end relative to the overhanging part 16 on the secured side to lock and secure the indexed position of the turret 3 through the clutch device 4.
In such a machine tool, a large clamping force is needed because in addition to the weight of the turret 3 equipped with a plurality of tools among which swiveling can be switched, a large load acts during processing and particularly during lathe turning. Therefore, a mainstream configuration has been one in which a hydraulic sliding mechanism is used rather than the air pressure as previously described in the driving of the sliding of the turret 3 in the automatic swiveling turret device, and after the turret has finished swiveling, the locked and secured state of the clutch is held under pressure by the hydraulic sliding mechanism which produces a large clamping force. However, with a configuration in which the turret 3 is slid to release the clutch device 4 by oil pressure produced by this large clamping force, a slide-driving force greater than necessary is produced when the turret 3 is slid in order to swivel (in order to release the clutch).
In other words, when the sliding movement gap 32 is narrowed and eliminated by the sliding for releasing the clutch, yielding a state of contact, a large sliding friction resistance is produced in the contacting surfaces during swiveling of the turret, because of the pushing by the oil pressure.
Specifically, when the turret 3 is slid back by oil pressure and the locked and secured state of the clutch device 4 is held under pressure, the large load during processing can be withstood, but there is also a risk that when the turret 3 is swiveled after the turret 3 is slid in order to release the clutch, a large slide pressing force due to the oil pressure will produce a large sliding friction resistance when the turret swivels, thereby causing wear to be more severe, durability to deteriorate, and galling to occur during swiveling.
In order to resolve such problems, there has been a need to provide a hydraulic pressure reducing mechanism or the like, wherein a bypass channel is interconnected with the previously isolated clutch-releasing pressure chamber 31, oil is fed from the clutch-releasing pressure chamber 31 into the opposite sliding movement gap 32 (the clutch pressure chamber 32) via the bypass channel, and the slide driving is reduced, when the channeling of the oil into the clutch-releasing pressure chamber 31 exceeds a predetermined pressure or when the turret slides in excess of a predetermined stroke, as shown in Unexamined Utility Model Application 57-149903, for example.
This complicates the structure and control, and presents problems in that, for example, the device becomes more expensive and less adapted to mass-production, or that, for example, the unclamping speed for releasing the clutch (swiveling the turret) has become slower. Therefore, to eliminate the use of oil pressure and limit resource consumption, the applicant has developed a turret device (Japanese Patent Publication No. 4383475) designed so that the turret 3 is slid by an air-pressure sliding mechanism that uses the air supply device as previously described, and this clutched state of the turret which has slid and is incapable of swiveling can be kept locked and secured by a wedge mechanism 24 for causing a wedge part 22 to engage with a wedge engagement part 21.
Specifically, the applicant has developed a highly innovative composite processing machine, wherein even though the pneumatic turret slide mechanism 15 may not produce drive force sufficient to directly withstand a large cutting force (lathe turning force), the weight of the turret 3 or a large cutting force can be sufficiently borne by the wedge mechanism 24, whereby the use of oil pressure can be eliminated, energy can be conserved, and resource consumption can be limited without impeding turret swiveling or the cutting function, there is no need for an oil pressure reducing mechanism that would require a complicated design or controls as previously described due to elimination the use of oil pressure, the swivel function can be easily ensured, the speed of unclamping for the purpose of swiveling is improved, etc.